In the field of semiconductors in recent years, higher integration and speeding up have become advanced, and the production of thinner wiring is required especially in high integration. As a result, in the manufacturing process for a semiconductor substrate, since the focal depth becomes shallower during the exposure of a photoresist, even more improvement in surface planarization is desired.
In the manufacturing process for a semiconductor substrate, for example, in the step of forming wiring or the step of shallow trench isolation, there are numerous fine projections and dents having various widths due to formation of channels for wiring or embedding on the substrate. Therefore, planarization of the projections and dents is desired.
When the dents and projections on the surface of this substrate are polished, there are some disadvantages that the projection portions are rapidly polished with a polishing liquid containing only an abrasive, and the dent portions are also polished at the same time, so that it is time-consuming, and it is also necessary to polish a considerable amount of a member of a surface to be polished, to achieve substantial planarization of both the dent and projection portions.
Therefore, a technique for obtaining a plane semiconductor substrate by using a polishing composition capable of selectively polishing projection portions is known from JP 2001-7059 A.
However, the action of the polishing composition is very sensitive to the concentration of an additive and planarization properties are lowered (lowering of the polishing rate of projection portions or generation of dishing) even with a slight change in the polishing conditions such as states of a polishing pad. Therefore, it has been difficult to control the manufacturing process.